根据短文内容判断正 （T）误 （F） 。
What is time? We can't see it and we can't catch hold of it, but we can feel it passing by.
Time is always with us in our life. When we are at the table, time passes away while we are eating.
When we wash our faces, time slips away(消失) in front of us. And when we play, time goes by
unnoticeably(不被注意地) .
Time is fair to every one of us. If you make the best use of it, time will give you a lot. Otherwise,
you will miss a lot. The lost time will not be found again.
Today, time is becoming more and more valuable to us. You can always hear people say,"Time is
money. Time is life. "It warns us not to waste any time.
My friends, we must keep in mind the saying,"Time and tide wait for no man. "Now we are still
young. It's high time for us to learn more. We must make the best use of every minute and be the
masters of time.
( )1. Time is a thing that we can see and catch hold of.
( )2. Time is fair to everybody.
( )3. The lost time will be found again.
( )4. Only young people shouldn't waste time.
( )5. "Time is money. Time is life" ,we must be the masters of time.
f(t)f’(2a-t)dt．证明：F(2a)-2F(a)=f2(a)-f(0)f(2a)．